Stereoscopic microscope

ABSTRACT

Stereoscopic microscope comprising an optical inverter system ( 21   a,    21   b ) for erecting a pseudo-stereoscopic image and reversing the viewing beams thereof, wherein the inverter system comprises at least one deflector element ( 21   a   , 21   b ) having a focal power.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority of German patent applicationnumber 103 32 603.0 filed Jul. 17, 2003.

FIELD OF THE INVENTION

The present invention relates to a stereoscopic microscope of a typehaving an optical inverter system for erecting a pseudo-stereoscopicimage and reversing of the viewing beams thereof.

BACKGROUND OF THE INVENTION

Ophthalmological microscopes as such are known. They comprise a mainobjective, a magnification system disposed thereafter, i.e. behind themain objective, and a binocular system with oculars (eyepieces). Inorder to provide a stereoscopic microscope in a magnification system,which is, for example, designed as a zoom system, the main beam path,which passes the main objective lens may be split into a number of beampaths. Further, ophthalmological microscopes are known, which allow fora simultaneous inspection of the object by a first user (main surgeon)and a second user (assistant).

Intraocular surgery requires supplementary optical systems, for examplein order to microscopically inspect the fundus or parts of the vitreousbody of a human eye, which are close to the fundus. These consist oflenses, which are disposed in front of the main objective at the side ofthe object.

A supplementary optical system of this kind is described in the brochure“SDI II, BIOM II” of Oculus Optikgerate GmbH published in 1998, as wellas in U.S. Pat. No. 4,856,872. This supplementary optical systemcomprises a lens (ophthalmoscopical lens) to be positioned close to theobject to be inspected, and a lens (reduction lens), which is positionedcloser to the main objective.

From DE 41 14 646 C2 a solution is known, according to which anophtalmological attachment for a surgical microscope is accomodated inan attachment housing, which is laterally positionable with respect tothe main objective. The attachment comprises an ophtalmoscopical lens,an optical image erecting system and a slideable lens (correcting lens)for focussing.

The image erecting system is needed, because the supplementary opticalsystems reverse the microscopic image with respect to its heightextension and its lateral extension, thereby giving apseudo-stereoscopic virtual image. This means among other things thatthe front and the back of depth perception of the intermediate imagecreated by the ophtalmoscopical lens are reversed. However, in order toallow for microsurgical operations, an erected, stereoscopically correctimage is required. For this reason, in order to avoid the otherwiseresulting pseudo-stereoscopic effect in viewing, a reversal (anexchange) of the two viewing beam paths (reversal of pupils) must occursimultaneously to the required erection of the image. An especiallypreferred embodiment of such an optical system for erecting images isknown as SDI-System (stereoscopic diagonal inverter). A system of thiskind is known, for example, from the already mentioned brochure “SDI II,BIOM II” dating from 1998. However, the use of such SDI systems isaccompanied by considerable disadvantages for the microscope system orthe image quality of the microscope. In particular, adapting the opticalbeam path of these supplementary systems to that of the stereomicroscope has proved to be very cumbersome. Frequently, this results inpoor image quality and field clipping, which is caused by insufficientmechanical adaptation of the SDI-system to the microscope. Further, theoverall height of such SDI-systems influences the ergonomic overallheight of the microscope in a negative way.

SUMMARY OF THE INVENTION

For a stereoscopic microscope, the present invention aims to invertlaterally inverted, pseudo-stereoscopic image in a simple way, i.e. toimage in a laterally correct and stereoscopically correct manner.

This aim is achieved by means of a stereoscopic microscope comprising anoptical inverter system for erecting a pseudo-stereoscopic image andreversing the viewing beam paths of the pseudo-stereoscopic image,wherein the inverter system includes a deflector element having a focalpower.

With the inventive measure of providing an optical inverter system forerecting a pseudo-stereoscopic image and reversing the viewing beamsthereof, comprising at least one deflector element provided with a focalpower it is possible in a simple way to reduce the overall height of thestereoscopic microscope as compared to conventional solutions. Hence, itis possible in an advantageous manner to reduce the ergonomic overallheight of the microscope as well.

It is advisable that a stereoscopic microscope comprises two deflectorelements provided with a focal power. Thereby, it is possible, forexample, to deflect a beam path, especially a horizontally proceedingone, which is incident upon the first deflector element, initially intoa vertical (perpendicular) direction, and subsequently, by means of afurther deflection by the second deflecting element to create a beampath, which proceeds substantially parallel to the original horizontalbeam path. Thereby, a laterally and vertically correct image is createdalong the beam path, which proceeds vertically between the twomicroscope planes. Therefore, this vertically proceeding beam path maybe used in an optimal manner. Thereby, the overall size of astereoscopic microscope may be kept very small, and an availableconstruction space may be exploited in an optimal manner.

According to an especially preferred embodiment of the stereoscopicmicroscope according to the invention, at least one deflector element ofthe inverter system is designed as a concave mirror. Concave mirrors maybe provided in a simple and cost-effective way, and may further beadjusted easily. It is further imaginable to employ deflector prismsdesigned to have a focal power as deflector elements.

It is advisable that the stereoscopic microscope according to theinvention comprises a main objective, which defines a first opticalaxis, and deflector elements to deflect a beam path proceeding parallelto the first optical axis along a second optical axis in a first planeof the microscope, which extends at an angle, in particularsubstantially perpendicularly to the first optical axis, andsubsequently to be directed along a third optical axis in a second planeof the microscope, which extends substantially parallel to and above thefirst plane of the microscope. A stereoscopic microscope constructed inthis way has a small overall height, as compared to conventionalsolutions, because a major part of the necessary or appropriate opticalcomponents, may be provided in the first and second planes of themicroscope, which preferably extend horizontally.

According to a further preferred embodiment of the stereoscopicmicroscope according to the invention, it comprises a magnificationsystem, especially a zoom system, which is provided in the first orsecond plane of the microscope, along the second or third optical axis,respectively, and comprises at least two stereoscopic viewing channels.Such a zoom system may be positioned selectively in front of or behindthe inverter system. In particular, it proves to be especiallybeneficial to position it behind the inverter system, because in thiscase the requirements for the deflector elements of the inverter systemwith respect to precision are comparatively low. It may also beconsidered to provide the magnification system between the two planes ofthe microscope along the vertically proceeding beam path. In that themagnification system is positioned accordingly, the overall heightand/or the horizontal overall length of the microscope, may beinfluenced in the desired way.

It proves to be especially advantageous that at least one of theinverter system's deflector elements with a focal power additionallyserves as deflector element for deflecting beam paths between the first,second and third optical axes. By means of such a multiple functionalityof the deflector elements, construction space may be kept small in aneffective way.

The stereoscopic microscope according to the invention preferably has andecoupling means to decouple an assistant beam path from a maininvestigator beam path. By means of such an decoupling means, which may,for example, be provided as a physical or a geometrical beam splitter,an inspection by the main investigator and an inspection by theassistant may be provided in a simple way.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now described with reference to the accompanyingdrawings. Therein,

FIG. 1 shows a lateral schematic sectional view of a preferredembodiment of a stereoscopic microscope according to the invention,having an ophthalmological attachment provided therebefore, and

FIG. 2 shows the microscope according to FIG. 1 without ophthalmologicalattachment and accordingly adapted optical system.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, a preferred embodiment of the stereoscopic microscopeaccording to the invention as a whole is designated by reference numeral100. The stereoscopic microscope comprises a microscope body 102, inwhich a main objective 2 and a magnification system 7, which isespecially designed as a zoom system, are provided as opticalcomponents.

The microscope further comprises deflector elements 5, 21 a, 21 b. Bymeans of these deflector elements, viewing beams 12 a to 12 h, whichemerge from an object 40 to be inspected, and which at first pass themain objective 2 substantially (at 21 a) in vertical direction along theoptical axis thereof, which is referred to as first optical axis 11 a inthe following, are deflectable into two substantially horizontallyextending planes I and II of the microscope (at 12 b, 12 d). It can beseen that the magnifying system 7, in the embodiment shown is disposedin the second plane II of the microscope. The optical axes in the firstand second planes of the microscope are subsequently referred to assecond and third optical axes 11 b, 11 d, respectively.

At the object side of the magnifying system 7 supplementary opticalcomponents are provided, selectively in the first and/or second plane I,II of the microscope, along the respective optical axes, which as awhole are referred to by reference numeral 8 herein, which comprise forexample filters, laser shutters, optical dividers or elements forcreating intermediate images.

The microscope shown is designed for simultaneous inspection of theobject 40 by a main surgeon and by an assistant. To achieve this aim, adeflecting element or a decoupling means 9 is provided in the secondplane II of the microscope, effecting the decoupling of the viewing beampath 12 g for the assistant with respect to the viewing beam path 12 dfor the main surgeon. The inspection of the object 40 by the assistanttakes place in a third plane III of the microscope.

The stereoscopic splitting of the (uniform) beam path 12 a, which isincident upon the main objective 2, may occur at an arbitrary positionwithin the microscope housing 102 in a manner, which as such is known.It is advisable that the stereoscopic splitting is carried out by meansof the magnifying system 7, which may comprise, for example, two or fourstereoscopic viewing channels. It may also be considered to provide themagnifying system 7 with four stereoscopic viewing channels grouped inpairs, wherein one pair of stereoscopic viewing channels is provided forthe main surgeon and the other pair for the assistant.

The provision of four magnifying channels within the context of themagnification system enables the implementation of a small verticaldistance between the respective viewing axis and the object to beinspected both for the main surgeon as well as for the assistant. It isadvisable that two magnifying channels for the magnifying system, inparticular the magnifying channels for the main surgeon, proceedhorizontally at the same height, whereas two further magnifying channelsproceed parallel herewith, i.e. also horizontally, with a verticalspacing. These magnifying channels with vertical spacing are especiallyuseable for the assistant. In this respect, it is especially possiblethat the magnifying channels provided with vertical spacing proceedabove or below, respectively, the center of the connecting line betweenthe magnifying channels for the main surgeon provided at the sameheight. Thereby, an especially dense packaging of the four magnifyingchannels is provided, whereby an especially small overall height of thestereoscopic microscope according to the invention may be achieved. Forreasons of clarity, in FIGS. 1 and 2, only single viewing beam paths areshown. In particular, in the second plane II of the microscope, theviewing beam path is referred to by 12 d. As an explanation, it shall benoted that the two viewing beam paths for the main surgeon are arrangedbehind each other in the viewing direction of FIGS. 1 and 2, so thatonly one of these viewing beam paths can be shown. The viewing beampaths in the second plane of the microscope, which have a verticalspacing, and which, by the deflector element 9, are deflected into thethird plane II of the microscope, are not shown in detail. Further, withrespect to the preferred embodiment of the magnification system 7, thevertically proceeding viewing beam path 12 g is only a schematicsimplification, since actually in this embodiment, as shown in FIGS. 1and 2, a total of two viewing beam paths which proceed verticallyparallel to each other, are deflected to the third plane of themicroscope. A complete illustration of this preferred embodiment of amagnification system is disclosed in DE 102 55 960, to which referenceis made herewith.

By means of binocular tubes (not shown), the decoupling means 9 allowfor a stereoscopic inspection of the object 40 by the main surgeonand/or the assistant.

It is advisable, that in order to obtain a further deflection of thestereoscopic viewing beam paths for the main surgeon, a furtherdeflection element 6 is provided behind the decoupling means 9, by meansof which the (stereoscopic) viewing beam paths (at 12 e) for the mainsurgeon can be deflected from the second plane II back to, for example,the first plane I of the microscope. In the first plane I, a furtherdeflection element 16 is provided, by means of which the viewing beampaths for the main surgeon are deflected into a substantially horizontaldirection again. The beam paths proceeding to a binocular tube (notshown) in plane I of the microscope are referred to by 12 f.

If, however, an inspection of object 40 by the main surgeon is desiredin the second plane II of the microscope, the deflector element 6 may beomitted, or it may be provided in a semi-transparent or relocatablemanner. In this case, the viewing beam paths for the main surgeonreferred to by 12 h result.

For the assistant, a further deflector element 10 is provided in thethird plane III of the microscope, by means of which the beam paths 12g, which are decoupled by decoupling means 9 (and are substantiallyvertically proceeding), are deflectable to the third plane of themicroscope (i.e. substantially in a horizontal direction). It isadvisable that depending on the orientation of the assistant beam paths,the deflector element 10 may be pivoted about an axis 13 or an axis,which proceeds perpendicular to this axis, so that by means of thebinocular tube for the assistant (not shown), an assistant's viewing ispossible, in the example shown into the drawing plane or out of thedrawing plane.

An illumination system of the microscope shown is as a whole referred toby 3,4, wherein a fiber cable for illumination means 3 is referred to by4. By means of a deflector element 3 a, light from the fiber cable isincident, at a desired angle, upon the object 40 to be illuminated. Theoptical axis of fiber cable 4 is designated by 12.

The microscope 100 is further provided with a supplementary opticalsystem 30, 32, which allows the carrying out of intraocular surgery.

The supplementary optical system comprises an ophthalmoscopical lens orfundus lens 30, and a correcting lens 32. The ophthalmoscopical lens 30serves to optically compensate the focal power of the eye.

Since the ophthalmoscopical lens 30 and the correcting lens 32 arejointy used in intraocular surgery they may, by means of a pivotingmechanism (not shown), be pivoted out of the beam path 12 a from betweenobject 40 and main objective 2 or out of the optical axis 11 a of themain objective 2, respectively. By means of this ability to be pivoted,it is ensured that microscope 100 can also be applied for other surgicalinterventions, which do not require such supplementary optical systems.

With respect to the operation of the supplementary optical system, itshall be noted that the ophthalmoscopical lens 30 creates a firstintermediate image 31 of the object 40 before the main objective lens 2of the microscope 100. The image 31 created by ophthalmoscopical lens 30is vertically and laterally reversed (pseudo-stereoscopic). It isadvisable that the correcting lens 32 is provided in such a way that itmay be displaced along the optical axis 11 a, as is indicated by thedouble-sided arrow. By means of displacing the correcting lens 32, it ispossible, for example, to focus onto a section of interest of the objector eye 40, without having to carry out adjustments to the optical systeminside housing 102.

As explained, the intermediate image 31 is laterally and verticallyreversed, i.e. pseudo-stereoscopic. In order to provide a vertically andlaterally correct image, the deflector elements 21 a, 21 b are designedas concave mirrors (mirrors with a radius other than ∞). In particular,the following propagation of the viewing beam results: by means of thecorrecting or auxiliary lens 32, or, if applicable (subsequent todeflecting by deflecting element 5) of the supplementary opticalcomponents 8, the beam paths, which result from the vertical andlaterally reversed intermediate image 31 are converted into a beam path,which is substantially parallel to the axis along the optical axis 11 bof the first plane I of the microscope. This beam path parallel to theaxis is by means of concave mirror 21 a, deflected into a furtherintermediate image 22 in the vertical beam path 12 c between the twoplanes I, II of the microscope. This intermediate image 22 is laterallycorrect and vertically correct, i.e. stereoscopic. By means of theconcave mirror 21 b, this intermediate image 22 is imaged to infinity inthe second plane II of the microscope again (the beam path beingsubstantially parallel to the axis). The magnification system 7 ispreferrably designed as a four-channel zoom system along the thirdoptical axis 11 d, whereby, as already mentionned, the stereoscopicsplitting for the main surgeon and the assistant is effected. The doublefunctionality of the deflector elements 21 a, 21 b should once again benoted. On the one hand, they serve to deflect the beam paths and therebyto optimally exploit the space inside the microscope body 102, on theother hand, they serve to invert a pseudo-stereoscopic intermediateimage, whereby the number of optical components is reduced, as comparedto conventional solutions.

Therefore, the deflector elements 21 a, 21 b both serve to deflect therespective viewing beam paths inside the body of the microscope, as wellas to create an image or image to infinity, respectively, whereby animage erection of an inverted, pseudo-stereoscopic intermediate image isprovided in a simple and cost-effective manner.

Therefore, according to the invention, it is possible to replaceconventionally used SDI-systems, which comprise relatively complex prismsystems and plane mirror systems, by simple convex mirrors 21 a, 21 b.It is also possible to provide the double functionality provided by theconcave mirrors 21 a, 21 b by means of deflector prisms provided with afocal power. Instead of deflector elements 21 a or 21 b, it might alsobe considered to provide deflector element 5 with a focal power.Thereby, the inverted intermediate image would be created in the firstplane I of the microscope.

If microscope 100 is to be used without the ophthalmoscopical attachment30, 32, said attachment is removeable from the beam path 12 a,especially it may be pivoted out. A respective repositioning mechanism,which may be designed to be manually driven or motor-driven, is notshown in detail. In this case, as shown in FIG. 2, the deflectorelements 21 a, 21 b, which are designed as concave mirrors, are removedfrom the viewing beam path (for example by pivoting) and replaced byconventional, planar deflector mirrors 22 a, 22 b. Apart from this, theconfiguration of the microscope according to FIG. 2 corresponds to thataccording to FIG. 1, so that a repeated detailed description may beomitted. It should merely be noted that in exchanging the concavemirrors 21 a, 21 b by conventional deflector elements 22 a, 22 b, whichare designed as planar mirrors, further possibilities to couple out beampaths are given, as they are referred to as a whole as 50 in FIG. 2. Tothis end, the deflector elements 22 a, 22 b may be designedsemi-transparently, whereby it is advisable to provide a furtherdeflector element 51.

It is advisable that the deflector elements 21 a, 21 b and 22 a, 22 b,respectively, are coupled to the ophthalmoscopical attachment, so thatin case the ophtalmoscopical attachment is removed from the beam path 12a, the deflector elements 21 a, 21 b are automatically or motor-drivenexchanged by the deflector elements 22 a, 22 b and vice versa. Thereby,if elements 30 and 32 of the supplementary optical system are not used,it is possible to also remove the focally-powered inverter systemelements 21 a, 21 b and replace them with conventional planar deflectionelements 21 a, 21 b in a simple manner. An electromechanical coupling 60is shown in FIG. 1 for accomplishing the joint removal or insertion ofthe inverter system and supplementary optical system into or out of thebeam path of the microscope.

Finally, it should be noted that it is possible to mirror-in data at thepositions of the deflector elements 6 or 51. At these positions, it isfurther advantageous to employ an optical beam divider, for example fora documenting device.

List of Reference Signs

-   2 main objective-   3 illumination means-   3 a deflector element of the illumination device-   4 fiber optic cable-   5, 6 deflector elements-   7 magnification system (zoom system)-   8 supplementary optical components-   9 deflector element (out-coupling means)-   10 deflector element-   11 a, 11 b, 11 c, 11 d optical axes-   12 optical axis of fiber cable-   12 a-12 h viewing beams-   13 pivot axis of deflector element 10-   16 deflector element-   21 a, 21 b deflector elements (concave mirrors)-   22 a, 22 b deflector elements (planar mirrors)-   22 intermediate image-   30 ophthalmoscopical lens (fundus lens)-   31 intermediate image-   32 correcting lens-   40 object-   50 decoupled beam paths-   51 deflector element-   60 electromechanical coupling-   100 stereoscopic microscope-   102 microscope body (housing)-   I, II, III planes of the microscope

1. A stereoscopic microscope comprising: a main objective; a beam pathpassing through the main objective; means for splitting the beam pathinto a pair of stereoscopic viewing beam paths; and an optical invertersystem for erecting a pseudo-stereoscopic image and reversing theviewing beam paths of the pseudo-stereoscopic image, wherein theinverter system includes a deflector element having a focal power. 2.The stereoscopic microscope according to claim 1, wherein the invertersystem includes two deflector elements each having a focal power.
 3. Thestereoscopic microscope according to claim 1, wherein the deflectorelement is a concave mirror.
 4. The stereoscopic microscope according toclaim 2, wherein at least one of the two deflector elements is a concavemirror.
 5. The stereoscopic microscope according to claim 1, wherein themain objective defines a first optical axis, and the microscope furthercomprises a plurality of deflector elements for deflecting a beam pathrunning parallel to the first optical axis along a second optical axiswithin a first plane I of the microscope that is substantiallyperpendicular to the first optical axis and subsequently along a thirdoptical axis within a second plane II of the microscope that issubstantially parallel to and above the first plane I of the microscope.6. The stereoscopic microscope according to claim 5, further comprisinga zoom system provided along the second optical axis or the thirdoptical axis, wherein the zoom system includes at least two stereoscopicviewing channels.
 7. The stereoscopic microscope according to claim 5,wherein the deflector element of the inverter system is one of theplurality of deflector elements.
 8. The stereoscopic microscopeaccording to claim 1, further comprising a decoupling device arranged tocouple out an assistant viewing beam path.
 9. The stereoscopicmicroscope according to claim 1, further comprising a supplementaryoptical system selectively insertable into the beam path in front of themain objective, the supplementary optical system including anophthalmoscopical lens and a correcting lens.
 10. The stereoscopicmicroscope according to claim 9, wherein the inverter system and thesupplementary optical system are electromechanically coupled to oneanother.